Injectable snoring implant

ABSTRACT

A method and apparatus for treating snoring of a patient includes providing an implant for altering a dynamic response of a soft palate of the patient to airflow past the soft palate. The implant is embedded in the soft palate to alter the dynamic response. For example, the implant has a mass, stiffness or dampening sufficient to alter the dynamic response following the implantation without substantially impairing a function of the soft palate to close a nasal passage of the patient during swallowing.

This application is a continuation of U.S. patent application Ser. No.10/629,490 filed Jul. 29, 2003; which is a continuation of U.S. patentapplication Ser. No. 09/872,545 filed Jun. 1, 2001, now U.S. Pat. No.6,626,181; which is a continuation of U.S. patent application Ser. No.09/398,991 filed Sep. 17, 1999, now U.S. Pat. No. 6,250,307; whichapplications are incorporated herein by reference.

BACKGROUND

1. Field of the Invention

This invention is directed to methods and apparatuses for treatingsnoring.

2. Description of the Prior Art

Snoring has received increased scientific and academic attention. Onepublication estimates that up to 20% of the adult population snoreshabitually. Huang, et al., “Biomechanics of Snoring”, Endeavour, p.96-100, Vol. 19, No. 3 (1995). Snoring can be a serious cause of maritaldiscord. In addition, snoring can present a serious health risk to thesnorer. In 10% of habitual snorers, collapse of the airway during sleepcan lead to obstructive sleep apnea syndrome. Id.

Notwithstanding numerous efforts to address snoring, effective treatmentof snoring has been elusive. Such treatment may include mouth guards orother appliances worn by the snorer during sleep. However, patients findsuch appliances uncomfortable and frequently discontinue use (presumablyadding to marital stress).

Electrical stimulation of the soft palate has been suggested to treatsnoring and obstructive sleep apnea. See, e.g., Schwartz, et al.,“Effects of electrical stimulation to the soft palate on snoring andobstructive sleep apnea”, J. Prosthetic Dentistry, pp. 273-281 (1996).Devices to apply such stimulation are described in U.S. Pat. Nos.5,284,161 and 5,792,067. Such devices are appliances requiring patientadherence to a regimen of use as well as subjecting the patient todiscomfort during sleep. Electrical stimulation to treat sleep apnea isdiscussed in Wiltfang, et al., “First results on daytime submandibularelectrostimulation of suprahyoidal muscles to prevent night-timehypopharyngeal collapse in obstructive sleep apnea syndrome”,International Journal of Oral & Maxillofacial Surgery, pp. 21-25 (1999).

Surgical treatments have been employed. One such treatment isuvulopalatopharyngoplasty. In this procedure, so-called laser ablationis used to remove about 2 cm of the trailing edge of the soft palatethereby reducing the soft palate's ability to flutter between the tongueand the pharyngeal wall of the throat. The procedure is frequentlyeffective to abate snoring but is painful and frequently results inundesirable side effects. Namely, removal of the soft palate trailingedge comprises the soft palate's ability to seal off nasal passagesduring swallowing and speech. In an estimated 25% ofuvulopalatopharyngoplasty patients, fluid escapes from the mouth intothe nose while drinking. Huang, et al., supra at 99.Uvulopalatopharyngoplasty (UPPP) is also described in Harries, et al.,“The Surgical treatment of snoring”, Journal of Laryngology and Otology,pp. 1105-1106 (1996) which describes removal of up to 1.5 cm of the softpalate. Assessment of snoring treatment is discussed in Cole, et al.,“Snoring: A review and a Reassessment”, Journal of Otolaryngoloy, pp.303-306 (1995).

Huang, et al., supra, describe the soft palate and palatal snoring as anoscillating system which responds to airflow over the soft palate.Resulting flutter of the soft palate (rapidly opening and closing airpassages) is a dynamic response generating sounds associated withsnoring. Huang, et al., propose an alternative touvulopalatopharyngoplasty. The proposal includes using a surgical laserto create scar tissue on the surface of the soft palate. The scar is toreduce flexibility of the soft palate to reduce palatal flutter. Huang,et al., report initial results of complete or near-complete reduction insnoring and reduced side effects.

Surgical procedures such as uvulopalatopharyngoplasty and those proposedby Huang, et al., continue to have problems. The area of surgicaltreatment (i.e., removal of palatal tissue or scarring of palataltissue) may be more than is necessary to treat the patient's condition.Surgical lasers are expensive. The proposed procedures are painful withdrawn out and uncomfortable healing periods. The procedures havecomplications and side effects and variable efficacy (e.g., Huang, etal., report promising results in 75% of patients suggesting a fullquarter of patients are not effectively treated after painful surgery).The procedures may involve lasting discomfort. For example, scar tissueon the soft palate may present a continuing irritant to the patient.Importantly, the procedures are not reversible in the event they happento induce adverse side effects not justified by the benefits of thesurgery.

SUMMARY OF THE INVENTION

According to a preferred embodiment of the present invention, methodsand apparatuses are disclosed for treating snoring of a patient. Theinvention includes providing an implant for altering a dynamic responseof a soft palate of the patient to airflow past the soft palate. Theimplant is embedded in the soft palate to alter the dynamic response.For example, the implant has a mass, stiffness or dampening sufficientto alter the dynamic response following the implantation withoutsubstantially impairing a function of the soft palate to close a nasalpassage of the patient during swallowing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view of a portion of a human head showing asoft palate in a relaxed state and in relation in adjacent anatomicalfeatures;

FIG. 2 is a portion of the view of FIG. 1 showing the soft palate in aflexed state;

FIG. 3 is a front view of an interior of the mouth shown in FIG. 1 andshowing an area to be ablated according to a first prior art surgicalprocedure;

FIG. 4 is the view of FIG. 3 and showing an area to be scarred accordingto a second prior art surgical procedure;

FIG. 5 is a schematic representation of a spring-mass system model ofthe soft palate;

FIG. 6 is the view of FIG. 1 with the soft palate containing an implantaccording to a first embodiment of the present invention;

FIG. 7 is the view of FIG. 3 showing the embodiment of FIG. 6;

FIG. 8 is a cross-sectional view of the implant of FIG. 6;

FIG. 9 is a first modification of the implant of FIG. 8 having a tissuein-growth layer;

FIG. 10 is a second modification of the implant of FIG. 8 having asmooth outer layer;

FIG. 11 is the view of FIG. 6 with the soft palate containing an implantaccording to a second embodiment of the present invention;

FIG. 12 is the view of FIG. 7 showing the embodiment of FIG. 11;

FIG. 13 is a perspective view of the implant of FIG. 11;

FIG. 14 is a cross-sectional view of the implant of FIG. 13;

FIG. 15 is a view of the implant of FIG. 14 with the implant pre-formedto assume the shape of a soft palate in a relaxed state;

FIG. 16 is the view of FIG. 14 with the implant constructed to havegreater flexion in a downward direction;

FIG. 17 is an exploded perspective view of first modification of theimplant of FIG. 13;

FIG. 18 is a perspective view of a modification of a housing of theembodiment of FIG. 17;

FIG. 19 is a side section view of a second modification of the implantof FIG. 13;

FIG. 20 is a cross-sectional view of an implant that is anotherembodiment of the present invention, the implant is shown in a flattenedorientation;

FIG. 21 is a cross-sectional view of the implant of FIG. 20 in anexpanded orientation;

FIG. 22 shows the implant of FIG. 20 in the flattened orientation andimplanted in the soft palate; and

FIG. 23 shows the implant in FIG. 21 in the expanded orientation andimplanted in the soft palate.

DESCRIPTION OF THE PREFERRED EMBODIMENT

For ease of understanding the present invention, the dynamics of snoringare explained with reference to FIGS. 1-4. The hard palate HP overliesthe tongue T and forms the roof of the mouth M. The hard palate HPincludes a bone support B and does not materially deform duringbreathing. The soft palate SP is soft and is made up of mucous membrane,fibrous and muscle tissue extending rearward from the hard palate HP. Aleading end LE of the soft palate SP is anchored to the trailing end ofthe hard palate HP. A trailing end TE of the soft palate SP isunattached. Since the soft palate SP is not structurally supported bybone or hard cartilage, the soft palate SP droops down from the plane ofthe hard palate HP in an arcuate geometry of repose.

The pharyngeal airway passes air from the mouth M and the nasal passagesN into the trachea TR. The portion of the pharyngeal airway definedbetween opposing surfaces of the upper surface of the soft palate SP andthe wall of the throat is the nasopharynx NP.

During normal breathing, the soft palate SP is in the relaxed stateshown in FIG. 1 with the nasopharynx NP unobstructed and with air freeto flow into the trachea TR from both the mouth M and the nostrils N.

During swallowing, the soft palate SP flexes and extends (as shown inFIG. 2) to close the nasopharynx NP thereby preventing fluid flow fromthe mouth M to the nasal passages N. Simultaneously, the epiglottis EPcloses the trachea TR so that food and drink pass only into theesophagus ES and not the trachea TR. The soft palate SP is a valve toprevent regurgitation of food into the nose N. The soft palate SP alsoregulates airflow through the nose N while talking. Since the softpalate SP performs such important functions, prior art techniques forsurgically altering the soft palate SP can compromise these functions.

The majority of snoring is caused by the soft palate SP flapping backand forth. If breathing is solely through the nose N with the mouthclosed, the trailing edge TE of the soft palate SP is sucked into thenasopharyngeal space NP obstructing the airway and subsequently fallsopening the airway in a repeating cycle. When the mouth is open, airflows over the upper and lower surfaces of the soft palate SP causingthe soft palate SP to flap up and down alternating in obstructing theoral and nasal passageways M, N. The snoring sound is generated byimpulses caused by rapid obstruction and opening of airways. Huang, etal., state the airway passage opening and closing occurs 50 times persecond during a snore. Huang, et al., utilize a spring-mass model (FIG.5) to illustrate oscillation of the soft palate in response to airflow(where the soft palate is the ball B of mass depending by a spring Sfrom a fixed anchor A).

Huang, et al., analogize the shortening of the soft palate SP inuvulopalatopharyngoplasty as effectively raising the critical air flowspeed at which soft palate flutter will occur. The shaded area SA inFIG. 3 shows the area of the trailing end TE of the soft palate SP to beremoved during this procedure. The alternative procedure proposed byHuang, et al., reduces the flexibility of the soft palate SP throughsurface scarring which is asserted as effecting the critical flow speed.The shaded area SA′ in FIG. 4 shows the area to be scarred by thisalternate procedure. In FIG. 4, dashed line L shows the demarcationbetween the soft and hard palates.

Using the spring-mass model of FIG. 5 as a convenient model of the softpalate SP, the present invention is directed to a surgical implant intothe soft palate SP to alter the elements of the model and thereby alterthe dynamic response of the soft palate SP to airflow. The implant canalter the mass of the model (the ball B of FIG. 5), the spring constantof the spring S, the dampening of the spring S or any combination ofthese elements. Unlike the prior art surgical techniques, the implantsthat will be described are easy to insert in a small incision resultingin reduced patient discomfort and are not exposed to the interior of themouth (such as the surface scarring of Huang, et al.) as a patientirritant. Also, as will be described, the degree of dynamic remodelingcan be fine tuned avoiding the need for excessive anatomicalmodification and are reversible in the event of adverse consequences.

FIGS. 6-7 illustrate a first embodiment of the present invention whereindividual units 10 of mass (in the form of implantable modular devicessuch as spheres or implants of other geometry) are imbedded in the softpalate SP in close proximity to the trailing end TE. With reference tothe model of FIG. 5, the spheres add mass to the mass-spring systemthereby altering dynamic response to airflow and adding resistance todisplacement and accelerating. The placement of the units 10 of massalso alter the location of the soft palate's center of mass furtheraltering the model and dynamic response.

The embodiment of FIGS. 6-10 is tunable to a particular patient in thatmultiple modules 10 can be implanted (as illustrated in FIG. 7). Thispermits the surgeon to progressively increase the number of implantedmodules 10 until the altered dynamic response is such that snoringinducing oscillation is abated at normal airflow. The individual modules10 may be placed into the soft palate SP through small individualincisions closed by sutures which is much less traumatic than the grossanatomical destruction of uvulopalatopharyngoplasty or the large surfacearea scarring proposed by Huang, et al.

Preferably, such modules 10 of mass are solid modules such as spheres ofbiocompatible material which are radiopaque (or radio-marked) andcompatible with magnetic resonance imaging (MRI). Titanium is such amaterial. By way of non-limiting example, the modules 10 of mass may beabout 2-4 mm in diameter. In the case of pure, non-sintered titanium,each such sphere 10 would add 0.15-1.22 gm of mass to the trailing endTE of the soft palate SP and contribute to re-modeling the massdistribution of the soft palate SP. An example of an alternativematerial is any biocompatible ceramic.

As shown in FIG. 9, the spheres (labeled 10′ to distinguish from theversion 10 of FIG. 8) may be sintered throughout or otherwise providedwith tissue growth inducing material 12 on their outer surface. Suchmaterial may be a sintered outer layer or a coating or covering such asa polyester fabric jacket. Such material permits and encourages tissuein-growth to secure the implant 10′ in place. Also, placement of animplant 10 or 10′ will induce a fibrotic response acting to stiffen thesoft palate SP (and further alter the dynamic response and resistance todisplacement and acceleration). A sintered or coated sphere 10′ willenhance the fibrotic response and resulting stiffening.

While tissue in-growth and enhanced fibrotic response have the benefitsdescribed above, such embodiments may make the implant 10′ moredifficult to remove in the event reversal of the procedure is desired.Therefore, as shown in FIG. 10 as an alternative, the spheres (labeled10″ to distinguish from the implants 10, 10′) may be coated with smoothcoating 14 (such as parylene or PTFE) to reduce fibrosis.

The embodiments of FIGS. 6-10 add to and relocate the mass of thespring-mass system of FIG. 5 to remodel the dynamic response. The amountof mass is selected to alter the dynamic response but not preclude thesoft palate SP being moved to close off nasal passages N duringswallowing. Through fibrotic response and incision healing, the spring Sof the model is stiffened.

In addition to modifying the mass profile of the spring-mass system, thespring component S of FIG. 5 can be modified (alone or in combinationwith mass modification) to alter dynamic response. FIG. 11-16 illustratean implant 20 in the form of a flexible strip for placement in the softpalate. The use of the term “strip” herein is not intended to be limitedto long, narrow implants but can also include plates or other geometriesimplanted to alter the dynamic model of the soft palate SP. Elongatedstrips are presently anticipated as a preferred geometry to facilitateease of implant.

The strip 20 has a transverse dimension less than a longitudinaldimension. By way of non-limiting example, the strip may have a lengthL_(S) of about 20-30 mm, a thickness T_(S) of about 2-4 mm and a widthW_(S) of 5-10 mm. As shown in FIG. 11, the strip 20 is embedded in thesoft palate SP with the longitudinal dimension L_(S) extending fromadjacent the hard palate HP toward the trailing end TE of the softpalate SP. As shown in FIG. 12, multiple strips 20 may be embedded inthe soft palate SP extending either straight rearward or angled to thesides while extending rearward. The strips 20 may be formed straight(FIG. 14) or pre-shaped (FIG. 15) to have a rest shape approximate tothe side-cross section shape of the soft palate in a relaxed state.

The strips 20 may be any flexible, biocompatible material and arepreferably radiopaque or radio-marked as well as MRI compatible. Thestrips 20 need not be elastic and having a material spring constantbiasing them to their original shape. Such strips 20 could simply beflexible, plastically deformable strips which are stiffer than the softpalate SP to reinforce the soft palate SP and assist the soft palate SPin resisting deflection due to airflow. Such stiffening of the softpalate SP stiffens and dampens the spring S in the spring-mass system ofFIG. 5 and alters the dynamic response of the soft palate SP. The strip20 may be a spring having a spring constant to further resist deflectionof the soft palate SP as well as urging the soft palate SP to therelaxed state of FIG. 5. The stiffness of the strip 20, a springconstant of the strip 20, and the number of strips 20, are selected toavoid preclusion of closure of the soft palate SP during swallowing.Examples of suitable materials include titanium and nitinol (awell-known nickel-titanium alloy). As with the examples of FIGS. 9 and10, the strips 20 may be provided with tissue in-growth surfaces or maybe coated as desired. Also, the strips may be structurally modified tocontrol their flexibility. In FIG. 16, the bottom 22 of the strip 20(facing the tongue after placement) is provided with transverse notches24 to enhance downward flexion of the strip 20 relative to upwardflexion of the strip 20 following placement.

FIG. 17 provides an alternative to the strips 20 of FIG. 13. In FIG. 17,the strip 20′ includes a housing 26 having an interior space 28 with anaccess opening 25. The interior space 28 extends in the longitudinaldimension of the housing 26. The strip 20′ further includes alongitudinal insert 32 sized to be passed through the access opening 25and into the space 28. By way of non-limiting example, the housing 26could be silicone rubber (with radio-markers, not shown, to indicateplacement) and the inserts 32 could be titanium rods or other flexiblemember. With the embodiment of FIG. 17, the housing 26 (without aninsert) may be embedded in the soft palate SP. The housing 26 actsindependently as a stiffening strip to add stiffness to the soft palateSP to alter the soft palate's dynamic response. In the event furtherstiffening or a spring action is desired, the implant 20′ can beselectively tuned to the patient's unique dynamic model by placing theinsert 32 into the space 28 at the time of initial surgery or during asubsequent procedure. The embodiment of FIG. 17, permits selection of aninsert 32 from a wide variety of materials and construction so that aninsert 32 of desired characteristics (e.g., stiffness and spring action)can be selected to be inserted in the space 28 and alter the dynamicresponse as desired. The embodiment of FIG. 17 also permits laterremoval of the insert 32 and replacement with a different insert 32 ofdifferent properties for post-surgery modification of the soft palate'sdynamic response.

The embodiment of FIG. 18 is similar to that of FIG. 17. The housing 26′is provided with multiple, parallel-aligned interior spaces 28′ andaccess openings 25′. In addition to the function and benefits of theembodiment of FIG. 17, the number of inserts 32 may be varied to alterand adjust the dynamic response of the soft palate SP.

FIG. 19 illustrates a still further embodiment of the strip implant. InFIG. 19, the strip 20′″ is a bladder having a housing 26″ in the form ofa completely sealed envelope of flexible synthetic material defining aninterior space 28″. The envelope 26″ is preferably self-sealingfollowing needle injection. Fluid is injected into the housing 26″(e.g., through hypodermic needle 40 injection) to stiffen the strip20′″. Addition of fluid further stiffens the strip 20′″ and furtheralters the dynamic response of the soft palate SP. Removal of fluidincreases the flexibility. Unlike the embodiments of FIG. 17 (whereinserts 32 are most effectively replaced post-operatively throughincision to alter flexibility), the embodiment of FIG. 19 permitsselectively varying flexibility of the soft palate SP through needleinjection. An alternative to FIG. 19 is to fill the space 28″ with aso-called phase change polymer and inject a stiffening agent into thespace 28″ to alter the flexibility of the polymer.

FIGS. 20-23 illustrate a still further embodiment of the presentinvention. In the foregoing embodiments, the spring-mass system of FIG.5 is altered by altering the mass of the soft palate SP or the springcharacteristics of the soft palate SP. The dynamic response can also bealtered by altering the force acting on the spring-mass system. Namely,the force acting on the soft palate SP is generated by airflow over thesurface of the soft palate. The soft palate acts as an airfoil whichgenerates lift in response to such airflow. By modifying thelongitudinal (i.e., anterior to posterior) cross-sectional geometry ofthe soft palate SP, the aerodynamic response and, accordingly, thedynamic response are altered.

In the embodiments of FIGS. 20-23, the implant 30 is inserted into thesoft palate SP through an incision. The implant 30 has an oval shape tocause deformation of the geometry of the soft palate SP. Prior toimplantation, the implant 30 is preferably formed as a flat oval (FIGS.20 and 22) for ease of insertion. After implantation, the implant 30expands to an enlarged oval (FIGS. 21 and 23). While such expansioncould be accomplished mechanically (i.e., through balloon expansion),the implant 30 is preferably formed as a shape-memory alloy (such asnitinol) which expands to the enlarged shape in response to the warmthof the body. In addition to changing the aerodynamics of the soft palateSP, the implant 30 can be constructed with a mass and stiffness asdesired to alter the spring and mass components of the spring-masssystem of FIG. 5.

The foregoing describes numerous embodiments of an invention for animplant for the soft palate to alter a dynamic response of the softpalate. The invention is much less traumatic than prior surgicaltreatments. Further, the invention permits use of reversible proceduresas well as procedures which can be selectively tuned both during surgeryand post-operatively. Having described the invention, alternatives andembodiments may occur to one of skill in the art. For example, thestrips of FIG. 13 may be encased coiled springs which may be tightenedto further stiffen the strips. Such strips may also be hinged segments.It is intended that such modifications and equivalents shall be includedwithin the scope of the following claims.

1-13. (canceled)
 14. An apparatus to brace or fixate tissue in targetedpharyngeal structures and/or individual anatomic components within thepharyngeal conduit comprising a material including one or more liquidcomponents that is injected into tissue as a liquid or slurry and thatsets in situ to create a non-liquid mechanical implant structure.
 15. Asystem comprising at least two apparatuses, at least one of theapparatuses comprising an apparatus as defined in claim
 14. 15. A methodfor implanting an apparatus in targeted pharyngeal structures and/orindividual anatomic components within the pharyngeal conduit comprisingthe steps of providing at least one apparatus as defined in claim 14,and injecting the apparatus in targeted pharyngeal structures and/orindividual anatomic components within the pharyngeal conduit.